[PATCH v2] net: Generalise wq_has_sleeper helper

From: Herbert Xu
Date: Thu Nov 26 2015 - 00:56:06 EST

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In reply to: David Miller: "Re: net: Generalise wq_has_sleeper helper"
Next in thread: David Miller: "Re: [PATCH v2] net: Generalise wq_has_sleeper helper"
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On Wed, Nov 25, 2015 at 11:37:29AM -0500, David Miller wrote:
>
> > Would be easier to refer to the comment that now adorns
> > waitqueue_active().
>
> Yeah, that might be a good idea. Herbert can you adjust this?

Sure, here is an updated patch. Note that this patch is based
on net-next where there is actually no comment above waitqueue_active.
But hopefully this will right itself once the trees are merged.

Thanks,

---8<---
The memory barrier in the helper wq_has_sleeper is needed by just
about every user of waitqueue_active. This patch generalises it
by making it take a wait_queue_head_t directly. The existing
helper is renamed to skwq_has_sleeper.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 0aa6fdf..fb99f30 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -106,7 +106,7 @@ static void aead_wmem_wakeup(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
POLLRDNORM |
POLLRDBAND);
@@ -157,7 +157,7 @@ static void aead_data_wakeup(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
POLLRDNORM |
POLLRDBAND);
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index af31a0e..0e6702e 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -238,7 +238,7 @@ static void skcipher_wmem_wakeup(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
POLLRDNORM |
POLLRDBAND);
@@ -288,7 +288,7 @@ static void skcipher_data_wakeup(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
POLLRDNORM |
POLLRDBAND);
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 1e1bf9f..6aa09a8 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -107,6 +107,27 @@ static inline int waitqueue_active(wait_queue_head_t *q)
return !list_empty(&q->task_list);
}

+/**
+ * wq_has_sleeper - check if there are any waiting processes
+ * @wq: wait queue head
+ *
+ * Returns true if wq has waiting processes
+ *
+ * Please refer to the comment for waitqueue_active.
+ */
+static inline bool wq_has_sleeper(wait_queue_head_t *wq)
+{
+ /*
+ * We need to be sure we are in sync with the
+ * add_wait_queue modifications to the wait queue.
+ *
+ * This memory barrier should be paired with one on the
+ * waiting side.
+ */
+ smp_mb();
+ return waitqueue_active(wq);
+}
+
extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
diff --git a/include/net/sock.h b/include/net/sock.h
index bbf7c2c..4adbe00 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -58,6 +58,7 @@
#include <linux/memcontrol.h>
#include <linux/static_key.h>
#include <linux/sched.h>
+#include <linux/wait.h>

#include <linux/filter.h>
#include <linux/rculist_nulls.h>
@@ -1879,12 +1880,12 @@ static inline bool sk_has_allocations(const struct sock *sk)
}

/**
- * wq_has_sleeper - check if there are any waiting processes
+ * skwq_has_sleeper - check if there are any waiting processes
* @wq: struct socket_wq
*
* Returns true if socket_wq has waiting processes
*
- * The purpose of the wq_has_sleeper and sock_poll_wait is to wrap the memory
+ * The purpose of the skwq_has_sleeper and sock_poll_wait is to wrap the memory
* barrier call. They were added due to the race found within the tcp code.
*
* Consider following tcp code paths:
@@ -1910,15 +1911,9 @@ static inline bool sk_has_allocations(const struct sock *sk)
* data on the socket.
*
*/
-static inline bool wq_has_sleeper(struct socket_wq *wq)
+static inline bool skwq_has_sleeper(struct socket_wq *wq)
{
- /* We need to be sure we are in sync with the
- * add_wait_queue modifications to the wait queue.
- *
- * This memory barrier is paired in the sock_poll_wait.
- */
- smp_mb();
- return wq && waitqueue_active(&wq->wait);
+ return wq && wq_has_sleeper(&wq->wait);
}

/**
diff --git a/net/atm/common.c b/net/atm/common.c
index 49a872d..6dc1230 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -96,7 +96,7 @@ static void vcc_def_wakeup(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up(&wq->wait);
rcu_read_unlock();
}
@@ -117,7 +117,7 @@ static void vcc_write_space(struct sock *sk)

if (vcc_writable(sk)) {
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible(&wq->wait);

sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
diff --git a/net/core/sock.c b/net/core/sock.c
index 1e4dd54..2769bd3a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2283,7 +2283,7 @@ static void sock_def_wakeup(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_all(&wq->wait);
rcu_read_unlock();
}
@@ -2294,7 +2294,7 @@ static void sock_def_error_report(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_poll(&wq->wait, POLLERR);
sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
rcu_read_unlock();
@@ -2306,7 +2306,7 @@ static void sock_def_readable(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLIN | POLLPRI |
POLLRDNORM | POLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
@@ -2324,7 +2324,7 @@ static void sock_def_write_space(struct sock *sk)
*/
if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) {
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
POLLWRNORM | POLLWRBAND);

diff --git a/net/core/stream.c b/net/core/stream.c
index d70f77a..8ff9d63 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -35,7 +35,7 @@ void sk_stream_write_space(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_poll(&wq->wait, POLLOUT |
POLLWRNORM | POLLWRBAND);
if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
diff --git a/net/dccp/output.c b/net/dccp/output.c
index 4ce912e..b66c84d 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -201,7 +201,7 @@ void dccp_write_space(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible(&wq->wait);
/* Should agree with poll, otherwise some programs break */
if (sock_writeable(sk))
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index fcb2752..4f0aa91 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -303,7 +303,7 @@ static void iucv_sock_wake_msglim(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_all(&wq->wait);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
rcu_read_unlock();
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 1f8a144..7e2d105 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -67,7 +67,7 @@ static void rxrpc_write_space(struct sock *sk)
if (rxrpc_writable(sk)) {
struct socket_wq *wq = rcu_dereference(sk->sk_wq);

- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible(&wq->wait);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
}
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 897c01c..ec10b66 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6978,7 +6978,7 @@ void sctp_data_ready(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
POLLRDNORM | POLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 552dbab..525acf6 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1492,7 +1492,7 @@ static void tipc_write_space(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
POLLWRNORM | POLLWRBAND);
rcu_read_unlock();
@@ -1509,7 +1509,7 @@ static void tipc_data_ready(struct sock *sk)

rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
POLLRDNORM | POLLRDBAND);
rcu_read_unlock();
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index aaa0b58..0446ff1 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -339,7 +339,7 @@ static void unix_write_space(struct sock *sk)
rcu_read_lock();
if (unix_writable(sk)) {
wq = rcu_dereference(sk->sk_wq);
- if (wq_has_sleeper(wq))
+ if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait,
POLLOUT | POLLWRNORM | POLLWRBAND);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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Next message: Rajendra Nayak: "[PATCH 2/6] clk: qcom: gdsc: Add support for gdscs with gds hw controller"
Previous message: Rajendra Nayak: "[PATCH 6/6] clk: qcom: mmcc8974: Use gdscs .parent and remove genpd calls"
In reply to: David Miller: "Re: net: Generalise wq_has_sleeper helper"
Next in thread: David Miller: "Re: [PATCH v2] net: Generalise wq_has_sleeper helper"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]